I wrote about this HERE a few months ago and there was considerable discussion stemming from that HERE.
My personal view is that if the resident is still there when the guests visit, then there’s not much harm. However, if they are using the service to get guests for an empty unit, it’s a short-term let.
Others may have less liberal views.
By the way, something else that hasn’t been raised is house swaps, when the resident clearly can’t be in residence when the guests arrive.